Photoelectric conversion device, imaging system, and movable object

ABSTRACT

A photoelectric conversion device includes a pixel unit having pixels arranged to form rows and columns, each including a transfer transistor that transfers charge in a photoelectric converter to an output unit, and a pixel control unit that controls the pixels. The pixel control unit is configured to supply a control signal in accordance with an exposure period individually defined for pixel blocks of the pixel unit to pixels of each pixel block and read out, from each pixel, a first signal obtained when the photoelectric converter is in a reset state and a second signal based on charge accumulated in the photoelectric converter during the exposure period. A period excluding both the exposure period and a readout period of the second signal corresponds to a reset period of the photoelectric converter. The transfer transistor is off in a readout period of the first and second signals.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a photoelectric conversion device, animaging system, and a movable object.

Description of the Related Art

In a solid-state imaging device such as a CMOS image sensor, atechnology to generate an image signal having a high dynamic range bycomposing two image signals obtained in different capturing conditionshas been proposed. Japanese Patent Application Laid-Open No. 2012-151847discloses a solid-state imaging device in which different exposure timecan be set on a pixel block basis in order to acquire two image signalsobtained in different capturing conditions. Further, Japanese PatentApplication Laid-Open No. 2012-151847 discloses that a photoelectricconverter is held in a reset state in a period other than the exposureperiod to prevent charge generated by the photoelectric converter in theperiod other than the exposure period from leaking out to an adjacentpixel and suppress image quality deterioration due to blooming.

In a solid-state imaging device, one of the widely used operations is toread out accumulated charge and read out noise, subtract a noise signalfrom a signal based on the accumulated charge, and thereby remove anoise component superimposed on the signal based on the accumulatedcharge. However, when the state of a transfer gate of a pixel circuit isdifferent between at the time of readout of accumulated charge and atthe time of readout of noise, this results in a large difference betweena noise amount superimposed on accumulated charge and a read out noiseamount. As a result, a noise component may not be appropriately removedfrom a signal based on accumulated charge, and image quality maydeteriorate.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a photoelectricconversion device and an imaging system in which different exposure timecan be set on a pixel block basis and a noise component can beappropriately removed from a signal based on accumulated charge.

According to one aspect of the present invention, provided is aphotoelectric conversion device including a pixel unit in which aplurality of pixels are arranged to form a plurality of rows and aplurality of columns and each of the plurality of pixels includes aphotoelectric converter that generates charge by photoelectricconversion, an output unit that outputs a signal in accordance with anamount of charge, and a transfer transistor that transfers charge in thephotoelectric converter to the output unit, and a pixel control unitthat controls operations of the plurality of pixels, wherein the pixelunit includes a plurality of pixel blocks each including one or more ofthe pixels, wherein the pixel control unit includes select circuitsrespectively associated to the plurality of pixel blocks, each of theselect circuit being configured to select a control signal to besupplied to the pixels of a corresponding pixel block, wherein the pixelcontrol unit is configured to supply, to the pixels of each of theplurality of pixel blocks, a control signal in accordance with anexposure period individually defined for the plurality of pixel blocks,wherein the pixel control unit is configured to read out, from each ofthe plurality of pixels, a first signal obtained when the photoelectricconverter is in a reset state and a second signal based on chargeaccumulated in the photoelectric converter during the exposure period,wherein a period excluding both the exposure period and a period inwhich the second signal is being read out corresponds to a reset periodof the photoelectric converter in which the photoelectric converter isbeing in the reset state, and wherein the transfer transistor is in anoff-state in a period in which the first signal is read out and a periodin which the second signal is read out.

Further, according to another aspect of the present invention, providedis a photoelectric conversion device including a pixel unit in which aplurality of pixels are arranged to form a plurality of rows and aplurality of columns and each of the plurality of pixels includes aphotoelectric converter that generates charge by photoelectricconversion, an output unit that outputs a signal in accordance with anamount of charge, and a transfer transistor that transfers charge in thephotoelectric converter to the output unit; and a pixel control unitthat controls operations of the plurality of pixels, wherein the pixelunit includes a plurality of pixel blocks each including one or more ofthe pixels, wherein the pixel control unit includes select circuitsrespectively associated to the plurality of pixel blocks, each of theselect circuits being configured to select a control signal to besupplied to the pixels of a corresponding pixel block, wherein the pixelcontrol unit is configured to supply, to the pixels of each of theplurality of pixel blocks, a control signal in accordance with anexposure period individually defined for the plurality of pixel blocks,wherein a period excluding both the exposure period and a period inwhich a signal based on charge accumulated in the photoelectricconverter during the exposure period is being read out corresponds to areset period of the photoelectric converter in which the photoelectricconverter is being in the reset state, and wherein each of the selectcircuits includes at least two signal level holding units eachconfigured to generate a control signal supplied to the transfertransistor of the pixels belonging to the corresponding pixel block.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a configuration example of aphotoelectric conversion device according to a first embodiment of thepresent invention.

FIG. 2 is a schematic diagram illustrating a configuration example of apixel unit in the photoelectric conversion device according to the firstembodiment of the present invention.

FIG. 3 is a circuit diagram illustrating a configuration example of apixel in the photoelectric conversion device according to the firstembodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration example of apixel control unit in the photoelectric conversion device according tothe first embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating a setting example of thelength of an exposure period for each pixel block.

FIG. 6A and FIG. 6B are schematic diagrams illustrating a drive exampleof the photoelectric conversion device according to the first embodimentof the present invention.

FIG. 7 is a block diagram illustrating a layout example of signal linesin the photoelectric conversion device according to the first embodimentof the present invention.

FIG. 8 is a timing diagram illustrating another drive example of thephotoelectric conversion device according to the first embodiment of thepresent invention.

FIG. 9 is a block diagram illustrating a configuration example of aphotoelectric conversion device according to a second embodiment of thepresent invention.

FIG. 10 is a block diagram illustrating an electrical connectionrelationship between substrates in the photoelectric conversion deviceaccording to the second embodiment of the present invention.

FIG. 11 is a block diagram illustrating a configuration example of aphotoelectric conversion device according to a third embodiment of thepresent invention.

FIG. 12A and FIG. 12B are schematic diagrams illustrating a driveexample of a photoelectric conversion device according to a fourthembodiment of the present invention.

FIG. 13 is a timing diagram illustrating another drive example of thephotoelectric conversion device according to the fourth embodiment ofthe present invention.

FIG. 14 is a block diagram illustrating a configuration example of apixel control unit in the photoelectric conversion device according tothe fourth embodiment of the present invention.

FIG. 15 is a block diagram illustrating a configuration example of aselect circuit in the photoelectric conversion device according to thefourth embodiment of the present invention.

FIG. 16, FIG. 17 and FIG. 18 are timing charts illustrating a driveexample of the photoelectric conversion device according to the fourthembodiment of the present invention.

FIG. 19 is a block diagram illustrating a configuration example of apixel control unit in a photoelectric conversion device according to afifth embodiment of the present invention.

FIG. 20 is a block diagram illustrating a configuration example of aselect circuit in the photoelectric conversion device according to thefifth embodiment of the present invention.

FIG. 21, FIG. 22 and FIG. 23 are timing charts illustrating a driveexample of the photoelectric conversion device according to the fifthembodiment of the present invention.

FIG. 24 is a block diagram illustrating a general configuration of animaging system according to a sixth embodiment of the present invention.

FIG. 25A is a diagram illustrating a configuration example of an imagingsystem according to a seventh embodiment of the present invention.

FIG. 25B is a diagram illustrating a configuration example of a movableobject according to the seventh embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS First Embodiment

A photoelectric conversion device and a method of driving the sameaccording to a first embodiment of the present invention will bedescribed with reference to FIG. 1 to FIG. 8.

First, a general configuration of the photoelectric conversion deviceaccording to the present embodiment will be described by using FIG. 1 toFIG. 4. FIG. 1 is a block diagram illustrating a configuration exampleof a photoelectric conversion device according to the presentembodiment. FIG. 2 is a schematic diagram illustrating a configurationexample of a pixel unit in the photoelectric conversion device accordingto the present embodiment. FIG. 3 is a circuit diagram illustrating aconfiguration example of a pixel in the photoelectric conversion deviceaccording to the present embodiment. FIG. 4 is a block diagramillustrating a configuration example of a pixel control unit in thephotoelectric conversion device according to the present embodiment.

As illustrated in FIG. 1, a photoelectric conversion device 100according to the present embodiment includes a pixel unit 101, a pixelcontrol unit 102, and a signal output unit 105. The pixel control unit102 is connected to the pixel unit 101 via a pixel control line group103 including a plurality of pixel control lines. The pixel unit 101 isconnected to the signal output unit 105 via a pixel output line group104 including a plurality of pixel output lines.

In the pixel unit 101, a plurality of pixels arranged in a matrix over aplurality of rows and a plurality of columns are provided. In FIG. 1,each of rectangular blocks depicted in the pixel unit 101 corresponds toone pixel. Note that, while FIG. 1 illustrates 300 pixels arranged on 15rows by 20 columns, the number of pixels arranged in the pixel unit 101is not particularly limited.

The pixel control unit 102 is a control circuit unit that controls theoperation of pixels arranged in the pixel unit 101 by using controlsignals supplied to the pixel unit 101 via the pixel control line group103. The pixel control line group 103 includes a plurality of pixelcontrol lines corresponding to a plurality of rows of the pixel arrayforming the pixel unit 101. Typically, each of the pixel control linesincludes a plurality of control lines. Each of the plurality of pixelcontrol lines is connected to each of the pixels arranged oncorresponding rows. Thereby, the pixel control unit 102 can control theoperation of the pixels arranged in the pixel unit 101 on a row basis.

The pixel output line group 104 includes a plurality of pixel outputlines corresponding to a plurality of columns of the pixel array formingthe pixel unit 101. Each of the plurality of pixel output lines isconnected to each of the pixels arranged on the corresponding columns.Thereby, it is possible to input signals read out from pixels onrespective columns arranged on a row selected by the pixel control unit102 to the signal output unit 105 via the pixel output line group 104.

The signal output unit 105 has a function of performing predeterminedsignal processing on a signal output from the pixel unit 101 and thenexternally outputting the processed signal. Signal processing performedby the signal output unit 105 is not particularly limited and mayinclude, for example, an amplifying process or an analog-to-digital (AD)conversion process.

The pixel control unit 102 and the signal output unit 105 may becontrolled by control signals supplied from a control unit (notillustrated) provided in the photoelectric conversion device 100 or theoutside of the photoelectric conversion device 100.

As illustrated in FIG. 2, the pixel unit 101 may be formed of aplurality of pixel blocks 201 each including one pixel P or a pluralityof pixels P. As an example, FIG. 2 illustrates the pixel unit 101 inwhich the pixel blocks 201 in which the pixels P are arranged in amatrix of 3 rows by 4 columns are arranged in a matrix of 3 rows by 3columns. Note that the configuration example illustrated in FIG. 2 isfor the purpose of simplified illustration, the pixel unit 101 and thepixel blocks 201 are not limited to the configuration illustrated inFIG. 2.

In the following description, a row in a unit of the pixel P may bereferred to as a pixel row, a column in a unit of the pixel P may bereferred to as a pixel column, a row in a unit of the pixel block 201may be referred to as a pixel block row, and a column in a unit of thepixel block 201 may be referred to as a pixel block column. In theexample of FIG. 2, it can be said that the pixel unit 101 is formed ofthe pixels P arranged in a matrix of 9 pixel rows by 12 pixel columnsand formed of the pixel blocks 201 arranged in a matrix of 3 pixel blockrows by 3 pixel block columns.

When the pixel P at a particular position in the pixel unit 101 isdenoted, coordinates expressed by (column number, row number) areattached to the reference P of the pixel. For example, in FIG. 2, apixel at the left upper corner is denoted by a reference P(1, 1), apixel at the left under corner is denoted by a reference P(1, 9), apixel at the right upper corner is denoted by a reference P(12, 1), anda pixel at the right under corner is denoted by a reference P(12, 9).

Further, when the pixel block 201 at a particular position in the pixelunit 101 is denoted, coordinates expressed by (column number, rownumber) are attached to the reference 201 of the pixel block. Note that“H” is attached to a column number of the pixel block 201 fordistinction from a column number of the pixel P. Further, “V” isattached to a row number of the pixel block 201 for distinction from arow number of the pixel P. For example, in FIG. 2, the pixel block atthe center on the under line is denoted by a reference 201(H2, V3).

As illustrated in FIG. 3, each of the pixels P includes a photoelectricconverter PD, a reset transistor M1, a transfer transistor M2, anamplifier transistor M3, and a select transistor M4. The photoelectricconverter PD is a photodiode, for example. The photodiode forming thephotoelectric converter PD has the anode connected to a referencevoltage node and the cathode connected to the source of the transfertransistor M2. The drain of the transfer transistor M2 is connected tothe source of the reset transistor M1 and the gate of the amplifiertransistor M3. The connection node of the drain of the transfertransistor M2, the source of the reset transistor M1, and gate of theamplifier transistor M3 is a so-called floating diffusion FD. Thefloating diffusion FD includes a capacitance component, functions as acharge holding portion, and forms a charge-to-voltage conversion unitmade of this capacitance component. The drain of the reset transistor M1and the drain of the amplifier transistor M3 are connected to a powersupply voltage node (voltage VDD). The source of the amplifiertransistor M3 is connected to the drain of the select transistor M4. Thesource of the select transistor M4 that is also the output node of thepixel P is connected to the pixel output line 106.

In the case of the pixel P illustrated in FIG. 3, a pixel control lineon each row forming the pixel control line group 103 includes a signalline connected to the gate of the transfer transistor M2, a signal lineconnected to the gate of the reset transistor M1, and a signal lineconnected to the gate of the select transistor M4. The transfertransistor M2 is supplied with a control signal PTX from the pixelcontrol unit 102 via a pixel control line on a corresponding row. Thereset transistor M1 is supplied with a control signal PRES from thepixel control unit 102 via a pixel control line on a corresponding row.The select transistor M4 is supplied with a control signal PSEL from thepixel control unit 102 via a pixel control line on a corresponding row.The plurality of pixels P forming the pixel unit 101 are controlled on arow basis by the control signals PTX, PRES, and PSEL supplied from thepixel control unit 102. When each transistor of the pixel P is formed ofan N-type transistor, a corresponding transistor is in an on-state whenthe control signal is at a High level (H level), and the correspondingtransistor is in an off-state when the control signal is at a Low level(L level).

Once an optical image of an object enters the pixel unit 101, thephotoelectric converter PD of each pixel P converts (photoelectricallyconverts) an incident light into an amount of charge in accordance withthe light amount of the incident light and accumulates the generatedcharge. When turned on, the transfer transistor M2 transfers charge heldby the photoelectric converter PD to the floating diffusion FD. Thefloating diffusion FD has a voltage in accordance with the amount ofcharge transferred from the photoelectric converter PD bycharge-to-voltage conversion due to the capacitance component of thefloating diffusion FD. The amplifier transistor M3 is configured suchthat the voltage VDD is supplied to the drain and a bias current issupplied to the source from a current source (not illustrated) via theselect transistor M4 and forms an amplifier unit (a source followercircuit) whose gate is the input node. Thereby, the amplifier transistorM3 outputs a signal based on the voltage of the floating diffusion FD tothe pixel output line 106 via the select transistor M4. When turned on,the reset transistor M1 resets the floating diffusion FD to a voltage inaccordance with the voltage VDD.

As illustrated in FIG. 4, the pixel control unit 102 includes a verticalscanning unit 301 and a plurality of select circuit blocks 302 inaccordance with each of the pixel block columns. For example, withrespect to the pixel unit 101 illustrated in FIG. 2, the pixel controlunit 102 includes three select circuit blocks 302_H1, 302_H2, and 302_H3corresponding to the pixel block columns H1, H2, and H3, respectively.

The vertical scanning unit 301 outputs the common control signals PRESand PSEL to all the pixels P belonging to the same row. The selectcircuit block 302 outputs the common control signal PTX to the pixels Pbelonging to the same row on the corresponding pixel block column. Thatis, the select circuit block 302_H1 outputs the common control signalPTX to the pixels P belonging to the same row of the pixel block columnH1. The select circuit block 302_H2 outputs the common control signalPTX to the pixels P belonging to the same row of the pixel block columnH2. The select circuit block 302_H3 outputs the common control signalPTX to the pixels P belonging to the same row of the pixel block columnH3.

FIG. 4 illustrates the control signals PTX, PRES, and PSEL output to thepixel unit 101 illustrated in FIG. 2, as an example. For example,control signals PRES_1 and PSEL_1 are output from the vertical scanningunit 301 to all the pixels P belonging to the first row. A commoncontrol signal PTX_H1_V1_1 is output from the select circuit block302_H1 to the pixels P belonging to the pixel block column H1, that is,the pixel P(1, 1) to the pixel P(4, 1) out of the pixels P belonging tothe first row. A common control signal PTX_H2_V1_1 is output from theselect circuit block 302_H2 to the pixels P belonging to the pixel blockcolumn H2, that is, the pixel P(5, 1) to the pixel P(8, 1) out of thepixels P belonging to the first row. A common control signal PTX_H3_V1_1is output from the select circuit block 302_H3 to the pixels P belongingto the pixel block column H3, that is, the pixel P(9, 1) to the pixelP(12, 1) out of the pixels P belonging to the first row. The sameapplies to the second row to the ninth row.

That is, control signals PRES_K and PSEL_K are output from the verticalscanning unit 301 to all the pixels P belonging to the N-th row on theM-th pixel block row VM. Here, K is expressed as K=M×N, where M is aninteger denoting a row number of the pixel block row and N is an integerdenoting a row number of a pixel row within the pixel block 201. Thatis, K corresponds to a row number on the pixel row within the pixel unit101.

Further, a common control signal PTX_H1_VM_N is output from the selectcircuit block 302_H1 to the pixels P belonging to the pixel block columnH1 out of the pixels P belonging to the N-th row in the M-th pixel blockrow VM. A common control signal PTX_H2_VM_N is output from the selectcircuit block 302_H2 to the pixels P belonging to the pixel block columnH2 out of the pixels P belonging to the N-th row in the M-th pixel blockrow VM. A common control signal PTX_H3_VM_N is output from the selectcircuit block 302_H3 to the pixels P belonging to the pixel block columnH3 out of the pixels P belonging to the N-th row in the M-th pixel blockrow VM.

By configuring the control signals PTX, PRES, and PSEL supplied from thepixel control unit 102 to the pixel unit 101 as described above, it ispossible to control the operation of the pixels P on a pixel block 201basis.

Next, a method of driving the photoelectric conversion device accordingto the present embodiment will be described by using FIG. 5 to FIG. 8.

FIG. 5 is a schematic diagram when the lengths of the exposure time ofthe pixels P are set on a pixel block 201 basis. In the example of FIG.5, the length of the exposure time of the pixels P belonging to thepixel blocks 201(H1, V1), 201(H2, V2), 201(H1, V3), and 201(H3, V3) isset to an exposure time T1. Further, the length of the exposure time ofthe pixels P belonging to the pixel blocks 201(H2, V1), 201(H3, V1),201(H1, V2), 201(H3, V2), and 201(H2, V3) is set to an exposure time T2.Here, the exposure time T1 is relatively longer than the exposure timeT2. In other words, the exposure time T2 is relatively shorter than theexposure time T1.

Note that, while the length of an exposure period is set to two types ofthe exposure time T1 and the exposure time T2 in the example of FIG. 5,the length of an exposure period may be set to three or more types ofexposure time.

FIG. 6A and FIG. 6B are schematic diagrams illustrating a drive examplefor implementing the operation illustrated in FIG. 5. FIG. 6Aillustrates a drive example on the pixel block column H1, and FIG. 6Billustrates a drive example on the pixel block column H2. In FIG. 6A andFIG. 6B, the horizontal axis represents time, and the vertical axisrepresents the pixel block row of the pixel unit 101. The verticalsynchronization signal VD illustrates the start of one frame incapturing.

In FIG. 6A and FIG. 6B, the reference “READ” indicates an operation (aread operation) to read out a signal based on charge accumulated in thephotoelectric converter PD of the pixel P. The references “SH1” and“SH2” indicate an operation (a shutter operation) to reset chargeaccumulated in the photoelectric converter PD of the pixel P. AnSH-signal is input for multiple times at different timings in one frame,and different exposure time can be selected on a pixel block 201 basisby selection of enable/disable of the SH-signal on a pixel block 201basis. In this example, two SH-signals of the operations “SH1” and “SH2”are assumed. Note that the selection of enable/disable is performed bycontrolling the control signal PTX_output to each pixel P by the selectcircuit block 302.

A signal output from the pixel P is based on charge accumulated in thephotoelectric converter PD during a period (an exposure period) fromlast input enabled “SH” to “READ”. In the example of FIG. 6A, since theoperation “SH1” is enabled and the operation “SH2” is disabled for thepixel blocks 201(H1, V1) and 201(H1, V3), the period from “SH1” to“READ” is the exposure period (the exposure time T1). Further, since theoperation “SH2” is enabled and the operation “SH1” is disabled for thepixel block 201(H1, V2), the period from “SH2” to “READ” is the exposureperiod (the exposure time T2). In the example of FIG. 6B, since theoperation “SH2” is enabled and the operation “SH1” is disabled for thepixel blocks 201(H2, V1) and 201(H2, V3), the period from “SH2” to“READ” is the exposure period (the exposure time T2). Further, since theoperation “SH1” is enabled and the operation “SH2” is disabled for thepixel block 201(H2, V2), the period from “SH1” to “READ” is the exposureperiod (the exposure time T1).

Note that, while the number of times of shutter operations is two,namely, “SH1” and “SH2” in the example of FIG. 6A and FIG. 6B, a use ofthree or more times of shutter operations can increase the number oftypes of variation of exposure time to three or more.

The reference “RST” indicates an operation to reset charge accumulatedin the photoelectric converter PD of the pixel P in a similar manner tothe operation “SH”. The references “RST1” and “RST2” correspond to theoperation “RST” input at different timings. The difference between theoperations “SH” and “RST” is the role thereof. While the operation “SH”has a role of resetting the photoelectric converter PD and startingaccumulation of charge to the photoelectric converter PD, the operation“RST” has a role of resetting charge accumulated in the photoelectricconverter PD of the pixel P in a period other than the exposure period.When the pixels P of different exposure periods are adjacent to eachother, and if no operation “RST” is performed, charge accumulated in aperiod other than an exposure period may leak out of the photoelectricconverter PD and leak into the adjacent pixel P that is in an exposureperiod. This phenomenon is called blooming and causes deterioration ofimage quality.

For example, in the example of FIG. 5 to FIG. 6B, the pixel P at theright end of the pixel block 201(H1, V2) and the pixel P on the left endof the pixel block 201(H2, V2) are adjacent pixels P having differentexposure periods from each other. However, since the operation “RST”(“RST2”) is performed in a period other than an exposure period on thepixel P of the pixel block 201(H1, V2) to prevent leakage of charge tothe horizontal direction from the photoelectric converter PD, bloomingcan be suppressed. Further, leakage of charge to the vertical directionfrom the pixel P of the pixel block 201(H1, V2) to the pixel block201(H1, V3) can also be prevented.

FIG. 7 is a block diagram illustrating a layout example of signal linesthat supply the control signal PTX in the photoelectric conversiondevice according to the present embodiment. The number of signal linesthat supply the control signal PTX_per one pixel row is equal to thenumber of pixel blocks 201 present on the pixel row thereof. Forexample, in the example of the pixel unit 101 illustrated in FIG. 2,three signal lines that supply the control signal PTX are arranged oneach pixel row. For example, a signal line that supplies a controlsignal PTX_H1_V1_1, a signal line that supplies a control signalPTX_H2_V1_1, and a signal line that supplies a control signalPTX_H3_V1_1 are arranged on the first pixel row. It is desirable thatthese signal lines have the same length so as to have the same parasiticcapacitance. With such a configuration, variation of timings of thecontrol signal PTX input to respective pixels P can be reduced.

FIG. 8 is a timing diagram illustrating another drive example of thephotoelectric conversion device according to the present embodiment.FIG. 8 illustrates timings of readout of charge from the photoelectricconverter PD and reset thereof for the first and second pixel rows. Inthis drive example, on the first row and the second row, the exposureperiod is changed for the pixel block columns H1, H2, an H3. Theoperations “READ”, “RST1”, “SH1”, “RST2”, and “SH2” in FIG. 8 are thesame as those of FIG. 6A and FIG. 6B.

Since charge accumulated in the photoelectric converter PD istransferred to the floating diffusion FD in response to transition ofthe control signal PTX to the H level, the control signal PTX is at theH level in each operation of “READ”, “SH”, and “RST”. In the operation“READ”, in response to control of the control signal PRES to the L leveland the control signal PSEL to the H level, a signal based on chargeaccumulated in the photoelectric converter PD during an exposure periodis read out. In the operations “SH” and “RST”, in response to control ofthe control signal PRES to the H level and the control signal PSEL tothe L level, charge accumulated in the photoelectric converter PD isreset.

When a single pixel row is focused on, the timing of “READ” in the pixelblock columns H1, H2, and H3 are the same. The difference in theexposure period of the pixels P on a single pixel row occurs due to adifference in the timing when the operation “SH” is last supplied, thatis, the timing when the photoelectric converter PD is last reset.

That is, on the first row, the operations “RST2” and “SH2” are disabledfor the pixel block columns H1 and H3. Thereby, the exposure period onthe pixel block columns H1 and H3 corresponds to the period from “SH1”to “READ”, and the exposure period on the pixel block column H2corresponds to the period from “SH2” to “READ”.

Further, on the second row, the operations “RST2” and “SH2” are disabledfor the pixel block column H2. Thereby, the exposure period on the pixelblock column H2 corresponds to the period from “SH1” to “READ”, and theexposure period on the pixel block columns H1 and H3 corresponds to theperiod from “SH2” to “READ”.

While the timing of each operation is shifted by one horizontal periodon the second row, the feature that the timings of “READ” on a singlepixel row are the same is the same as on the first row. That is, in thedrive example of FIG. 8, the timings of the first “READ” in respectivepixels P on the first row are the same at time t1, and the timings ofthe first “READ” in respective pixels P on the second row are the sameat time t2.

As described above, according to the present embodiment, it is possibleto change the exposure period on a pixel block basis and expand thedynamic range of a captured image. Further, it is possible to suppressblooming and prevent deterioration of image quality by preventingleakage of charge to adjacent pixels in the column direction and the rowdirection. Further, with the same length of signal lines that supply thecontrol signal PTX, the variation of timings of the PTX_signals input torespective pixels P is reduced, the variation of charge accumulationperiods is suppressed, and thereby deterioration of image quality can beprevented. Further, since a row scan of a rolling scheme can be appliedby causing charge readout (READ) timings within one pixel row to be thesame, this contributes to easy control.

Second Embodiment

A photoelectric conversion device according to a second embodiment ofthe present invention will be described with reference to FIG. 9 andFIG. 10. The same components as those of the photoelectric conversiondevice according to the first embodiment are labeled with the samereferences, and the description thereof will be omitted or simplified.FIG. 9 is a block diagram illustrating a configuration example of thephotoelectric conversion device according to the present embodiment.FIG. 10 is a block diagram illustrating an electrical connectionrelationship between substrates in the photoelectric conversion deviceaccording to the present embodiment.

As illustrated in FIG. 9, the photoelectric conversion device accordingto the present embodiment includes a first substrate 801 and a secondsubstrate 802. At least the pixel unit 101 is provided on the firstsubstrate 801. At least the select circuit block 302 is provided on thesecond substrate 802. In the configuration example illustrated in FIG.9, the vertical scanning unit 301 and the select circuit block 302 arearranged on the second substrate 802 side. The first substrate 801 andthe second substrate 802 are stacked to form a stacked-typephotoelectric conversion device. Other features or operations are thesame as those of the photoelectric conversion device according to thefirst embodiment.

In FIG. 10, a bold solid line is the boundary between the firstsubstrate 801 and the second substrate 802. The upper part of this solidline illustrates the first substrate 801, and the lower part of thissolid line illustrates the second substrate 802. In FIG. 10, to simplifythe drawing, pixel P(1, 1) to pixel P(8, 1) on the first row and pixelP(1, 2) to pixel P(4, 2) on the second row are extracted from the pixelunit 101 and illustrated.

Control signals PRES_1 and PSEL_1 are input to pixel P(1, 1) to pixelP(8, 1). The control signals PRES_1 and PSEL_1 are generated by thevertical scanning unit 301 provided on the second substrate 802 andsupplied from the second substrate 802 to the first substrate 801through a connection node 901. The control signals PRES_1 and PSEL_1 arebranched on the first substrate 801 into pixel P(1, 1) to pixel P(8, 1).

Similarly, control signals PRES_2 and PSEL_2 are input to pixel P(1, 2)to pixel P(4, 2). The control signals PRES_2 and PSEL_2 are generated bythe vertical scanning unit 301 provided on the second substrate 802 andsupplied from the second substrate 802 to the first substrate 801through a connection node 902. The control signals PRES_2 and PSEL_2 arebranched on the first substrate 801 into pixel P(1, 2) to pixel P(4, 2).

A control signal PTX_H1_V1_1 is input to pixel P(1, 1) to pixel P(4, 1).The control signal PTX_H1_V1_1 is generated by the select circuit block302 provided on the second substrate 802 and supplied from the secondsubstrate 802 to the first substrate 801 through a connection node 903.The control signal PTX_H1_V1_1 is connected to pixel P(1, 1) to pixelP(4, 1) by branch signal lines that are branched from a common signalline arranged on the first substrate 801.

Similarly, a control signal PTX_H2_V1_1 is input to pixel P(5, 1) topixel P(8, 1). The control signal PTX_H2_V1_1 is generated by the selectcircuit block 302 provided on the second substrate 802 and supplied fromthe second substrate 802 to the first substrate 801 through a connectionnode 905. The control signal PTX_H2_V1_1 is connected to pixel P(5, 1)to pixel P(8, 1) by branch signal lines branched from a common signalline arranged on the first substrate 801.

Further, the control signal PTX_H1_V1_2 is input to pixel P(1, 2) topixel P(4, 2). The control signal PTX_H1_V1_2 is generated by the selectcircuit block 302 provided on the second substrate 802 and supplied fromthe second substrate 802 to the first substrate 801 through theconnection node 904. The control signal PTX_H1_V1_2 is connected topixel P(1, 2) to pixel P(4, 2) by branch signal lines branched from acommon signal line arranged on the first substrate 801.

In such a way, with the configuration in which control signals arebranched on the first substrate 801, the number of electrical connectionnodes between the first substrate 801 and the second substrate 802 canbe reduced compared to a case where control signals are branched on thesecond substrate 802. This can reduce the probability of occurrence of aconnection failure due to a manufacturing defect and suppressmanufacturing variation. Therefore, the possibility that the value ofparasitic capacitance or parasitic resistance of respective lines variesis reduced, and variation in timings of change of signals for respectivepixels P can be reduced.

A plurality of connection nodes 901, a plurality of connection nodes902, a plurality of connection nodes 903, a plurality of connectionnodes 904, and a plurality of connection nodes 905 may be providedbetween the first substrate 801 and the second substrate 802, andrespective lines may be arranged in parallel. Such a configuration canfurther reduce the occurrence probability of a connection failure.

As described above, according to the present embodiment, since the pixelunit 101 is arranged on the first substrate 801 and the verticalscanning unit 301 and the select circuit block 302 are arranged on thesecond substrate 802, the number of pixel control lines passing throughthe region of the pixel unit 101 can be reduced. Thereby, the area thatcan be used as a region of the pixels P can be expanded, and thephotoelectric conversion efficiency of the pixels P can be increased.

Further, since a space occurs in a region 810 of the second substrate802 right below the pixel unit 101 by providing the pixel unit 101 onthe first substrate 801 side, it is possible to provide various functionblocks by using the region 810. In the example illustrated in FIG. 9,the region in which the pixel unit 101 is provided and the region inwhich the select circuit blocks 302 are provided do not overlap eachother in a plan view.

Further, since a connection failure between the first substrate 801 andthe second substrate 802 can be reduced, variation in timings of controlsignals input to respective pixels P can be reduced, and deteriorationof image quality can be suppressed.

Third Embodiment

A photoelectric conversion device according to a third embodiment of thepresent invention will be described with reference to FIG. 11. The samecomponents as those of the photoelectric conversion device according tothe first and second embodiments are labeled with the same references,and the description thereof will be omitted or simplified. FIG. 11 is ablock diagram illustrating a configuration example of the photoelectricconversion device according to the present embodiment.

The photoelectric conversion device according to the present embodimentis the same as the photoelectric conversion device according to thesecond embodiment in that at least the pixel unit 101 is provided on thefirst substrate 801 and at least the select circuit block 302 isprovided on the second substrate 802. The photoelectric conversiondevice according to the present embodiment is different from the secondembodiment in that the select circuit block 302 provided on the secondsubstrate 802 is provided in the region 810 of the second substrate 802right below the pixel unit 101. Other features and operations are thesame as those of the photoelectric conversion device according to thefirst and second embodiments.

That is, as illustrated in FIG. 11, the select circuit blocks 302_H1,302_H2, and 302_H3 provided on the second substrate 802 are arranged inthe region 810 right below the corresponding pixel block of the pixelunit 101 provided on the first substrate 801.

By arranging the select circuit block 302 in such a way, it is possibleto reduce the area of the first substrate 801 and the second substrate802 compared to the case of the second embodiment. Thereby, it ispossible to reduce the size of the photoelectric conversion device whilemaintaining the photoelectric conversion efficiency of the pixels P.

Fourth Embodiment

A photoelectric conversion device and a method of driving the sameaccording to a fourth embodiment of the present invention will bedescribed with reference to FIG. 12A to FIG. 18. The same components asthose of the photoelectric conversion device according to the first tothird embodiments are labeled with the same references, and thedescription thereof will be omitted or simplified.

FIG. 12A and FIG. 12B are schematic diagrams illustrating drive examplesof the photoelectric conversion device according to the presentembodiment. FIG. 12A and FIG. 12B illustrate drive examples forimplementing the operation illustrated in FIG. 5. FIG. 12A illustrates adrive example on the pixel block column H1, and FIG. 12B illustrates adrive example on the pixel block column H2. In FIG. 12A and FIG. 12B,the horizontal axis represents time, and the vertical axis representspixel block rows of the pixel unit 101. The vertical synchronizationsignal VD is a signal indicating the start of one frame in capturing.

In FIG. 12A and FIG. 12B, the operations “READ”, “SH1”, and “SH2” arethe same as those of FIG. 6A and FIG. 6B described in the firstembodiment. That is, the reference “READ” indicates an operation (a readoperation) to read out a signal based on charge accumulated in thephotoelectric converter PD of the pixel P. The references “SH1” and“SH2” indicate an operation (a shutter operation) to reset chargeaccumulated in the photoelectric converter PD of the pixel P. AnSH-signal is input for multiple times at different timings in one frame,and different exposure time can be selected on a pixel block 201 basisby selection of enable/disable of the SH-signal on a pixel block 201basis. In this example, two SH-signals of the operations “SH1” and “SH2”are provided. Note that the selection of enable/disable is performed bycontrolling the control signal PTX output to each pixel P by the selectcircuit block 302.

The drive method of the present embodiment is different from the firstto third embodiments in that there is no “RST” operation. Instead, inthe present embodiment, a period from “READ” to the last enabled “SH” isset to a reset period in which the photoelectric converter PD ismaintained in a reset state. The same features of any of the first tothird embodiments can be applied to other features.

In the present drive example, since the operation “SH1” is enabled andthe operation “SH2” is disabled for the pixel blocks 201(H1, V1) and201(H1, V3), the period from “SH1” to “READ” is an exposure period.Since the operation “SH2” is enabled for the pixel block 201(H1, V2),the period from “SH2” to “READ” is an exposure period. In any of thepixel blocks 201, the photoelectric converter PD is maintained in areset state in a period other than the exposure period. In other words,the role of the operation “READ” is to start reset of the photoelectricconverter PD after readout of charge, and the role of the operation “SH”is to release reset of the photoelectric converter PD.

Note that, while the number of times of shutter operations is two,namely, “SH1” and “SH2” in this drive example, a use of three or moretimes of shutter operations can increase the number of types ofvariation of the exposure period to three or more.

In the present drive example, since the photoelectric converter PD ismaintained in a reset state in a period other than the exposure period,there is a higher suppression effect against leakage of charge comparedto the case where the operation “RST” is intermittently introduced aswith the case of the first to third embodiments. That is, while there isa likelihood of leakage of charge out of the photoelectric converter PDwhen there is a high intensity incident light in a period from “RST” to“SH” in the first to third embodiments, there is no such likelihood inthe present drive example. Further, while it is necessary to calculatethe number of operations RST which is sufficient for suppressing leakageof charge as disclosed in the case of Japanese Patent ApplicationLaid-Open No. 2012-151847 in the operation to intermittently introducethe operation “RST”, such calculation is not necessary in the presentdrive example.

FIG. 13 is a timing diagram illustrating another drive example of thephotoelectric conversion device according to the present embodiment.FIG. 13 illustrates timings of readout and reset of charge from thephotoelectric converter PD for the first and second pixel rows. In thisdrive example, on the first row and the second row, the exposure periodis changed for the pixel block columns H1, H2, an H3. The operations“READ”, “SH1”, and “SH2” in FIG. 13 are the same as those of FIG. 12Aand FIG. 12B.

The period in which charge is accumulated in the photoelectric converterPD is a period in which the control signal PTX is at the L level, andthe period in which the photoelectric converter PD is reset is a periodin which the control signal PTX and the control signal PRES are at the Hlevel. That is, in the operation of “READ”, the control signal PTX is atthe H level, the control signal PRES is at the L level, and the controlsignal PSEL is at the H level. Further, in the operation of “SH”, thecontrol signal PTX is at the L level, the control signal PRES is at theH level, and the control signal PSEL is at the L level.

When a single pixel row is focused on, the timing of “READ” in the pixelblock columns H1, H2, and H3 are the same. The difference in theexposure period of the pixels P on a single pixel row occurs due to adifference in the timing when the operation “SH” is last supplied, thatis, the timing when the photoelectric converter PD is last reset.

That is, on the first row, the operation “SH2” is disabled for the pixelblock columns H1 and H3. Thereby, the exposure period on the pixel blockcolumns H1 and H3 corresponds to the period from “SH1” to “READ”, andthe exposure period on the pixel block column H2 corresponds to theperiod from “SH2” to “READ”.

Further, on the second row, the operation “SH2” is disabled for thepixel block column H2. Thereby, the exposure period on the pixel blockcolumn H2 corresponds to the period from “SH1” to “READ”, and theexposure period on the pixel block columns H1 and H3 corresponds to theperiod from “SH2” to “READ”.

While the timing of each operation is shifted by one horizontal periodon the second row, the feature that the timings of “READ” on a singlepixel row are the same is the same as on the first row. That is, in thedrive example of FIG. 13, the timings of the first “READ” in respectivepixels P on the first row are the same at time t5, and the timings ofthe first “READ” in respective pixels P on the second row are the sameat time t6.

FIG. 14 is a block diagram illustrating the configuration example of thepixel control unit 102 in the photoelectric conversion device accordingto the present embodiment.

The pixel control unit 102 includes the vertical scanning unit 301 andthe select circuit block 302, as described above. The select circuitblock 302 is divided into a plurality of select circuit blocks 302_HLcorresponding to pixel block columns of the pixel unit 101. Here, thereference L is an integer denoting a column number of the pixel block201. Out of these multiple select circuit blocks 302_HL, FIG. 14illustrates a select circuit block 302_H1 corresponding to the pixelblock column H1 and a select circuit block 302_H2 corresponding to thepixel block column H2. Each of the select circuit blocks 302_H outputsthe control signal PTX to the pixel block 201 on a corresponding pixelblock column.

Each of the select circuit blocks 302 HL includes a plurality of selectcircuits 1301 corresponding to the number of pixel rows and a selectcontrol circuit 1302. A common control signal PTX as a control signalused for a shutter operation is input from the vertical scanning unit301 to the select circuits 1301 arranged on the same pixel row.

For example, control signals PTX_READ_V1_1, PTX_SH1_V1_1, andPTX_SH2_V1_1 are input from the vertical scanning unit 301 to the selectcircuits 1301(H1, V1, 1) and 1301(H2, V1, 1) arranged on the first pixelrow. Similarly, control signals PTX_READ_V1_2, PTX_SH1_V1_2, andPTX_SH2_V1_2 are input from the vertical scanning unit 301 to the selectcircuits 1301(H1, V1, 2) and 1301(H2, V1, 2) arranged on the secondpixel row. Further, control signals PTX_READ_V3_3, PTX_SH1_V3_3, andPTX_SH2_V3_3 are input from the vertical scanning unit 301 to the selectcircuits 1301(H1, V3, 3) and 1301(H2, V3, 3) arranged on the ninth pixelrow.

The operations of the select circuits 1301 provided on the same pixelrow are distinguished by control signals supplied from the selectcontrol circuit 1302 provided on corresponding pixel block columns. Forexample, control signals PTHR_SH1_H1 and PTHR_SH2_H1 are input from theselect control circuit 1302_H1 to the select circuits 1301(H1, V1, 1),1301(H1, V1, 2), and 1301(H1, V3, 3). Further, control signalsPTHR_SH1_H2 and PTHR_SH2_H2 are input from the select control circuit1302_H2 to the select circuits 1301(H2, V1, 1), 1301(H2, V1, 2), and1301(H2, V3, 3).

That is, control signals PTX_READ_VM_N, PTX_SH1_VM_N, and PTX_SH2_VM_Nare input from the vertical scanning unit 301 to the select circuit 1301(HL, VM, N). Further, the control signals PTHR_SH1_HL and PTHR_SH2_HLare input from the select control circuit 1302_HL to the select circuit1301 (HL, VM, N). Here, the reference L denotes a column number of thepixel block 201, the reference M denotes a row number of the pixel block201, and the reference N is a row number of the pixel row within thepixel block 201.

Note that, in the present embodiment, two control signals, namely, thecontrol signal PTHR_SH1_HL and the control signal PTHR_SH2_HL aresupplied from the select control circuit 1302_HL to the select circuit1301(HL, VM, N) in association with the operations “SH1” and “SH2”. Thenumber of control signals PTHR may be appropriately changed inaccordance with the number of variations of the exposure period.

FIG. 15 illustrates a configuration example of the select circuit1301(H1, V1, 1) as an example of the select circuit 1301(HL, VM, N).

The select circuit 1301(H1, V1, 1) includes an AND gate for SH1 1303, anAND gate for SH2 1304, an OR gate for SH 1305, and an S-R latch circuit1306, for example. The S-R latch circuit 1306 is a latch circuit formedof an S-R (Set-Reset) flip-flop.

The control signal PTX_SH1_V1_1 and the control signal PTHR_SH1_H1 areinput to the AND gate for SH1 1303. That is, the control signalPTX_SH1_V1_1 is output to the OR gate for SH 1305 on the post-stage onlywhen the control signal PTHR_SH1_H1 is at the H level. Similarly, thecontrol signal PTX_SH2_V1_1 and the control signal PTHR_SH2_H1 are inputto the AND gate for SH2 1304. That is, the control signal PTX_SH2_V1_1is output to the OR gate for SH 1305 on the post-stage only when thecontrol signal PTHR SH2_H1 is at the H level. Note that selection ofpass/not-pass of the control signals PTX_SH1_V1_1 and PTX_SH2_V1_1corresponds to selection of enable/disable of the shutter operation.

The OR gate for SH 1305 outputs a control signal PTX_SH_H1_V1_1 inresponse to the output signal of the AND gate for SH1 1303 and theoutput signal of the AND gate for SH2 1304. The S-R latch circuit 1306outputs a control signal PTX_H1_V1_1 from the output terminal (Q) inresponse to the input of the control signal PTX_READ_V1_1 to the setterminal (S) and the input of the control signal PTX_SH_H1_V1_1 to thereset terminal (R). This control signal PTX_H1_V1_1 is the output signalof the select circuit 1301(H1, V1, 1). The S-R latch circuit 1306 isused for holding a reset state and an exposure state of thephotoelectric converter PD.

Next, the method of driving the photoelectric conversion deviceaccording to the present embodiment will be described by using FIG. 16to FIG. 18. FIG. 16 to FIG. 18 are timing charts illustrating a driveexample of the photoelectric conversion device according to the presentembodiment.

FIG. 16 and FIG. 17 are timing charts illustrating the operation of theselect circuit block 302_H1. FIG. 16 illustrates only the operation ofthe pixel block row V1. FIG. 17 illustrates only the operation of thepixel block row V2. The horizontal synchronization signal HD is a signalof notification of start timing of an operation for one row. Note thatthe time axis is common to FIG. 16 and FIG. 17.

First, the operation of the pixel block row V1 will be described byusing FIG. 16. First, at time t9, the control signal PTX_READ_V1_1 forthe first pixel row is controlled to the H level. At subsequent timet10, the control signal PTX_READ_V1_2 for the second pixel row iscontrolled to the H level. At subsequent time t11, the control signalPTX_READ_V1_3 for the third pixel row is controlled to the H level.Thereby, in the select circuit 1301 arranged on the pixel block row V1,the S-R latch circuit 1306 is set, and control signals PTX_H1_V1_1,PTX_H1_V1_2, and PTX_H1_V1_3 are at the H level, respectively. That is,time t9, time t10, and time t11 are timings of the start of resetperiods of the photoelectric converters PD of the pixels P belonging tothe first row, the second row, and the third row, respectively.

Subsequently, at time t11, the control signal PTX_SH1_V1_1 for the firstpixel row is controlled to the H level. At subsequent time t12, thecontrol signal PTX_SH1_V1_2 for the second pixel row is controlled tothe H level. At subsequent time t13, the control signal PTX_SH1_V1_3 forthe third pixel row is controlled to the H level. The control signalsPTX_SH1_V1_1, PTX_SH1_V1_2, and PTX_SH1_V1_3 correspond to the firstshutter operation (SH1).

At timings when the control signals PTX_SH1_V1_1, PTX_SH1_V1_2, andPTX_SH1_V1_3 transition to the H level, the control signals PTHR_SH1_H1is already at the H level. This indicates that all the control signalsPTX_SH1_V1_1, PTX_SH1_V1_2, and PTX_SH1_V1_3 are enabled. Thereby, thecontrol signal PTX_SH_H1_V1_1 is at the H level at time t11, the controlsignal PTX_SH_H1_V1_2 is at the H level at time t12, and the controlsignal PTX_SH_H1_V1_3 is at the H level at time t13.

The S-R latch circuit 1306 is reset in the select circuit 1301, and allthe control signals PTX_H1_V1_1, PTX_H1_V1_2, and PTX_H1_V1_3 are at theL level. That is, time t11, time t12, and time t13 are timings of theend of reset periods and also timings of the start of exposure periodsin the photoelectric converters PD of the pixel P belonging to the firstrow, the second row, and the third row, respectively. Note that, sincethe operation “SH1” is enabled, this exposure period is an exposureperiod for long-time exposure in which the exposure time is relativelylong.

Subsequently, at time t14, the control signals PTX_SH2_V1_1 for thefirst pixel row is controlled to the H level. At subsequent time t15,the control signals PTX_SH2_V1_2 for the second pixel row is controlledto the H level. At subsequent time t16, the control signals PTX_SH2_V1_3for the third pixel row is controlled to the H level. The controlsignals PTX_SH2_V1_1, PTX_SH2_V1_2, and PTX_SH2_V1_3 correspond to thesecond shutter operation (SH2).

At timings when the control signals PTX_SH2_V1_1, PTX_SH2_V1_2, andPTX_SH2_V1_3 transition to the H level, the control signals PTHR_SH2_H1is already at the L level. This indicates that all the control signalsPTX_SH2_V1_1, PTX_SH2_V1_2, and PTX_SH2_V1_3 are disabled. Thereby, thecontrol signal PTX_SH_H1_V1_1 remains at the L level at time t14.Further, the control signal PTX_SH_H1_V1_2 remains at the L level attime t15. Further, the control signal PTX_SH_H1_V1_3 remains at the Llevel at time t16.

Subsequently, at time t20, the control signal PTX_READ_V1_1 for thefirst pixel row is controlled to the H level. At subsequent time t21,the control signal PTX_READ_V1_2 for the second pixel row is controlledto the H level. At subsequent time t22, the control signal PTX_READ_V1_3for the third pixel row is controlled to the H level. This indicatesread operations to read charge accumulated in the photoelectricconverters PD, and the exposure periods on respective rows end upon thecompletion of these operations.

Subsequently, at time t22, the control signal PTX_SH1_V1_1 for the firstpixel row is controlled to the H level. At subsequent time t23, thecontrol signal PTX_SH1_V1_2 for the second pixel row is controlled tothe H level. At subsequent time t24, the control signal PTX_SH1_V1_3 forthe third pixel row is controlled to the H level. Thereby, all thecontrol signals PTX_H1_V1_1, PTX_H1_V1_2, and PTX_H1_V1_3 are at the Llevel. That is, time t22, time t23, and time t24 are the timings of thestart of next exposure periods in the photoelectric converters PD of thepixels P belonging to the first row, the second row, and the third row,respectively.

Next, the operation of the pixel block row V2 will be described by usingFIG. 17.

First, at time t12, the control signal PTX_READ_V2_1 for the first pixelrow is controlled to the H level. At subsequent time t13, the controlsignal PTX_READ_V2_2 for the second pixel row is controlled to the Hlevel. At subsequent time t14, the control signal PTX_READ_V2_3 for thethird pixel row is controlled to the H level. Thereby, in the selectcircuit 1301 arranged on the pixel block row V2, the S-R latch circuit1306 is set, and control signals PTX_H1_V2_1, PTX_H1_V2_2, andPTX_H1_V2_3 are at the H level, respectively. That is, time t12, timet13, and time t14 are timings of the start of reset periods of thephotoelectric converters PD of the pixels P belonging to the first row,the second row, and the third row, respectively.

Subsequently, at time t14, the control signal PTX_SH1_V2_1 for the firstpixel row is controlled to the H level. At subsequent time t15, thecontrol signal PTX_SH1_V2_2 for the second pixel row is controlled tothe H level. At subsequent time t16, the control signal PTX_SH1_V2_3 forthe third pixel row is controlled to the H level. The control signalsPTX_SH1_V2_1, PTX_SH1_V2_2, and PTX_SH1_V2_3 correspond to the firstshutter operation (SH1). At timings when the control signalsPTX_SH1_V2_1, PTX_SH1_V2_2, and PTX_SH1_V2_3 transition to the H level,the control signals PTHR_SH1_H1 is already at the L level. Thisindicates that all the control signals PTX_SH1_V2_1, PTX_SH1_V2_2, andPTX_SH1_V2_3 are disabled.

Thereby, the control signal PTX_H_H1_V2_1 remains at the L level at timet14. Further, the control signal PTX_SH_H1_V2_2 remains at the L levelat time t15. Further, the control signal PTX_SH_H1_V2_3 remains at the Llevel at time t16.

Subsequently, at time t17, the control signals PTX_SH2_V2_1 for thefirst pixel row is controlled to the H level. At subsequent time t18,the control signals PTX_SH2_V2_2 for the second pixel row is controlledto the H level. At subsequent time t19, the control signals PTX_SH2_V2_3for the third pixel row is controlled to the H level. The controlsignals PTX_SH2_V2_1, PTX_SH2_V2_2, and PTX_VH2_V2_3 correspond to thesecond shutter operation (SH2). At timings when the control signalsPTX_SH2_V2_1, PTX_SH2_V2_2, and PTX_SH2_V2 3 are controlled to the Hlevel, the control signals PTHR_SH2_H1 is already at the H level. Thisindicates that all the control signals PTX_SH2_V2_1, PTX_SH2_V2_2, andPTX_SH2_V2_3 are enabled.

Thereby, the control signal PTX_SH_H1_V2_1 is at the H level at timet17, the control signal PTX_SH_H1_V2_2 is at the H level at time t18,and the control signal PTX_SH_H1_V2_3 is at the H level at time t19. TheS-R latch circuit 1306 is reset in the select circuit 1301, and all thecontrol signals PTX_H1_V2_1, PTX_H1_V2_2, and PTX_H1_V2_3 are at the Llevel. That is, time t17, time t18, and time t19 are timings of the endof reset periods and also timings of the start of exposure periods inthe photoelectric converters PD of the pixel P belonging to the firstrow, the second row, and the third row, respectively. Note that, sincethe operation “SH2” is enabled, this exposure period is an exposureperiod for short-time exposure in which the exposure time is relativelyshort.

Subsequently, at time t23, the control signal PTX_READ_V2_1 for thefirst pixel row is controlled to the H level. At subsequent time t24,the control signal PTX_READ_V2_2 for the second pixel row is controlledto the H level. At subsequent time t25, the control signal PTX_READ_V2_3for the third pixel row is controlled to the H level. This indicatesread operations to read out charge accumulated in the photoelectricconverters PD, and the exposure periods on respective rows end upon thecompletion of these operations.

FIG. 18 is a timing chart illustrating the operation of the selectcircuit block 302_H2. FIG. 18 illustrates only the operation of thepixel block row V1. Note that the time axis is common to FIG. 16 to FIG.18.

First, at time t9, the control signal PTX_READ_V1_1 for the first pixelrow is controlled to the H level. At subsequent time t10, the controlsignal PTX_READ_V1_2 for the second pixel row is controlled to the Hlevel. At subsequent time t11, the control signal PTX_READ_V1_3 for thethird pixel row is controlled to the H level. Thereby, in the selectcircuit 1301 arranged on the pixel block row V1, the S-R latch circuit1306 is set, and control signals PTX_H2_V1_1, PTX_H2_V1_2, andPTX_H2_V1_3 are at the H level, respectively. That is, time t9, timet10, and time t11 are timings of the start of reset periods of thephotoelectric converters PD of the pixels P belonging to the first row,the second row, and the third row, respectively. This operation is thesame as that on the pixel block column H1.

Subsequently, at time t11, the control signal PTX_SH1_V1_1 for the firstpixel row is controlled to the H level. At subsequent time t12, thecontrol signal PTX_SH1_V1_2 for the second pixel row is controlled tothe H level. At subsequent time t13, the control signal PTX_SH1_V1_3 forthe third pixel row is controlled to the H level. The control signalsPTX_SH1_V1_1, PTX_SH1_V1_2, and PTX_SH1_V1_3 correspond to the firstshutter operation (SH1).

At timings when the control signals PTX_SH1_V1_1, PTX_SH1_V1_2, andPTX_SH1_V1_3 transition to the H level, the control signals PTHR_SH1_H2is already at the L level. This indicates that all the control signalsPTX_SH1_V1_1, PTX_SH1_V1_2, and PTX_SH1_V1_3 are disabled. Thereby, thecontrol signal PTX_SH_H2_V1_1 remains at the L level at time t11.Further, the control signal PTX_SH_H2_V1_2 remains at the L level attime t12. Further, the control signal PTX_SH_H2_V1_3 remains at the Llevel at time t13.

Subsequently, at time t14, the control signals PTX_SH2_V1_1 for thefirst pixel row is controlled to the H level. At subsequent time t15,the control signals PTX_SH2_V1_2 for the second pixel row is controlledto the H level. At subsequent time t16, the control signals PTX_SH2_V1_3for the third pixel row is controlled to the H level. The controlsignals PTX_SH2_V1_1, PTX_SH2_V1_2, and PTX_SH2_V1_3 correspond to thesecond shutter operation (SH2).

At timings when the control signals PTX_SH2_V1_1, PTX_SH2_V1_2, andPTX_SH2_V1_3 transition to the H level, the control signals PTHR_SH2_H2is already at the H level. This indicates that all the control signalsPTX_SH2_V1_1, PTX_SH2_V1_2, and PTX_SH2_V1_3 are enabled. Thereby, thecontrol signal PTX_SH_H2_V1_1 transitions to the H level at time t14,the control signal PTX_SH_H2_V1_2 transitions to the H level at timet15, and the control signal PTX_SH_H2_V1_3 transitions to the H level attime t16.

The S-R latch circuit 1306 is reset in the select circuit 1301, and allthe control signals PTX_H2_V1_1, PTX_H2_V1_2, and PTX_H2_V1_3 are at theL level. That is, time t14, time t15, and time t16 are timings of theend of reset periods and also timings of the start of exposure periodsin the photoelectric converters PD of the pixel P belonging to the firstrow, the second row, and the third row, respectively. Note that, sincethe operation “SH2” is enabled, this exposure period is an exposureperiod for short-time exposure.

Subsequently, at time t20, the control signal PTX_READ_V1_1 for thefirst pixel row is controlled to the H level. At subsequent time t21,the control signal PTX_READ_V1_2 for the second pixel row is controlledto the H level. At subsequent time t22, the control signal PTX_READ_V1_3for the third pixel row is controlled to the H level. This indicatesread operations to read out charge accumulated in the photoelectricconverters PD, and the exposure periods on respective rows end upon thecompletion of these operations.

As described above, according to the present embodiment, since thephotoelectric converter PD is held in a reset state out of an exposureperiod, the effect of suppressing charge leakage is higher than in acase where the operation “RST” is intermittently introduced. That is,while there is a likelihood in the first to third embodiments that alight of high intensity is received in a period from “RST” to “SH” andcharge leaks out of the photoelectric converter PD, there is no suchlikelihood in the present embodiment. Further, while the operation inwhich the operation “RST” is intermittently introduced requirescalculation of the number of times of operations “RST” which issufficient for suppressing charge leakage as disclosed in JapanesePatent Application Laid-Open No. 2012-151847, the present embodimentdoes not require such an operation. Further, by providing a latchcircuit within the pixel control unit 102, it is possible to realize theoperation to hold a reset state of the photoelectric converter PD byusing a logic circuit. Thereby, circuit design is easier than a casewhere an exposure period is controlled by an analog circuit, no analognoise occurs in a circuit operation, and therefore variation in theexposure period can be suppressed.

Fifth Embodiment

A photoelectric conversion device and a method of driving the sameaccording to a fifth embodiment of the present invention will bedescribed with reference to FIG. 19 to FIG. 23. The same components asthose of the photoelectric conversion device according to the first tofourth embodiments are labeled with the same references, and thedescription thereof will be omitted or simplified.

The present embodiment is different from the fourth embodiment in that,in an operation to read out charge from the photoelectric converter PD(read operation), an operation to control the control signal PTX isperformed in the order of the H level, the L level, and the H level.Further, the present embodiment is difference from the fourth embodimentin that the select circuit block 302 is formed by using an S-R latchcircuit and a D-type flip-flop circuit to realize the above operation.

FIG. 19 is a block diagram illustrating a configuration example of thepixel control unit 102 in the photoelectric conversion device accordingto the present embodiment. The entire configuration of the pixel controlunit 102 in the photoelectric conversion device according to the presentembodiment is the same as that of the pixel control unit 102 in thephotoelectric conversion device according to the fourth embodimentexcept that a control signal PLAT D is input commonly to all the selectcircuits 1301 as illustrated in FIG. 19.

FIG. 20 is a circuit diagram illustrating a configuration example of theselect circuit 1301 in the photoelectric conversion device according tothe present embodiment. FIG. 20 illustrates a configuration example ofthe select circuit 1301(H1, V1, 1) as an example of the select circuit1301(HL, VM, N).

The select circuit 1301(H1, V1, 1) includes an AND gate for SH1 1502, anAND gate for SH2 1503, an OR gate for SH 1504, an S-R latch circuit1505, a D latch circuit 1506, and an OR gate for output 1507, forexample. The S-R latch circuit 1505 is a latch circuit formed of an S-Rflip-flop. The D latch circuit 1506 is a latch circuit formed of aD-type flip-flop.

The control signal PTX_SH1_V1_1 and the control signal PTHR_SH1_H1 areinput to the AND gate for SH1 1502. That is, the control signalPTX_SH1_V1_1 is output to the OR gate for SH 1504 on the post-stage onlywhen the control signal PTHR_SH1_H1 is at the H level. Similarly, thecontrol signal PTX_SH2_V1_1 and the control signal PTHR_SH2_H1 are inputto the AND gate for SH2 1503. That is, the control signal PTX_SH2_V1_1is output to the OR gate for SH 1504 on the post-stage only when thecontrol signal PTHR_SH2_H1 is at the H level. Note that selection ofpass/not-pass of the control signals PTX_SH1_V1_1 and PTX_SH2_V1_1corresponds to selection of enable/disable of the shutter operation. TheOR gate for SH 1504 outputs the control signals PTX_SH_H1_V1_1 inresponse to an output signal of the AND gate for SH1 1502 and an outputsignal of the AND gate for SH2 1503.

The S-R latch circuit 1505 outputs a control signal PTX_SRQ_H1_V1_1 fromthe output terminal (Q) in response to the input of the control signalPTX_READ_V1_1 to the set terminal (S) and the input of the controlsignal PTX_SH_H1_V1_1 to the reset terminal (R). The D latch circuit1506 outputs a control signal PTX_DQ_H1_V1_1 from the output terminal(Q) in response to the input of a control signal PTX_SRQ_H1_V1_1 to thedata terminal (D) and the input of the control signal PLAT_D to theclock terminal. The OR gate for output 1507 outputs the control signalPTX_H1_V1_1 in response to the input of the control signal PTX_READ_V1_1and the control signal PTX_DQ_H1_V1_1. This control signal PTX_H1_V1_1is the output signal of the select circuit 1301 (H1, V1, 1).

The S-R latch circuit 1505 is used for holding a reset state and anexposure state of the photoelectric converter PD. Further, the D latchcircuit 1506 is used for controlling start/end timings of a reset stateand an exposure state.

As described above, the select circuit 1301 in the photoelectricconversion device according to the present embodiment includes at leasttwo signal level holding units used for generating control signalssupplied to transfer transistors of pixels belonging to a correspondingpixel block row.

A signal level holding unit arranged on the pre-stage out of the twosignal level holding units holds the level of the output signal at the Hlevel during a period from a rising edge of a control signal indicatinga read timing to a rising edge of a control signal indicating aneffective reset timing. This pre-stage signal level holding unitcorresponds to the S-R latch circuit 1505 in the select circuit 1301 ofFIG. 20.

A signal level holding unit arranged on the post-stage out of the twosignal level holding units holds the level of the output signal at the Hlevel in response to the output signal of the pre-stage signal levelholding unit and a timing control signal (control signal PLAT_D)indicating a start timing of a reset period of the photoelectricconverter. This post-stage signal level holding unit corresponds to theD latch circuit 1506 in the select circuit 1301 of FIG. 20. The timingcontrol signal is a signal that is input commonly to all the selectcircuits 1301.

Next, the method of driving the photoelectric conversion deviceaccording to the present embodiment will be described by using FIG. 21to FIG. 23. FIG. 21 to FIG. 23 are timing charts illustrating anoperation example of the photoelectric conversion device according tothe present embodiment.

FIG. 21 and FIG. 22 are timing charts illustrating the operation of theselect circuit block 302 H1. FIG. 21 illustrates only the operation ofthe pixel block row V1. FIG. 22 illustrates only the operation of thepixel block row V2. Note that the time axis is common to FIG. 21 andFIG. 22.

First, the operation of the pixel block row V1 will be described byusing FIG. 21.

First, in the period from time t27 to time t27′, the control signalPTX_READ_V1_1 for the first pixel row is controlled to the H level.Thereby, in the select circuit 1301(H1, V1, 1), the control signalPTX_H1_V1_1 transitions to the H level and, at the same time, the S-Rlatch circuit 1505 is set and the control signal PTX_SRQ_H1_V1_1transitions to the H level.

Subsequently, at time t28, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the H-levelcontrol signal PTX_DQ_H1_V1_1 in response to the H-level control signalPTX_SRQ_H1_V1_1. Thereby, the control signal PTX_H1_V1_1 that is theoutput signal of the OR gate for output 1507 transitions to the H level.

Note that, since the control signal PTX_READ_V1_1 has returned to the Llevel at the time of time t27′ before time t28, the control signalPTX_H1_V1_1 has returned to the L level in the period from time t27′ totime t28. Therefore, the start timing of a reset period of thephotoelectric converters PD in the pixels P belonging to the first rowis at time t28 when the control signal PLAT_D transitions to the Hlevel. The relationship of the order of these timings (the relationshipof the order that the control signal PTX_READ transitions to the L levelbefore the control signal PLAT_D transitions to the H level when onehorizontal period is focused on) is the same in the operation of all thesubsequent select circuits 1301.

Subsequently, at time t29, the control signal PTX_READ_V1_2 for thesecond pixel row is controlled to the H level. Thereby, in the selectcircuit 1301(H1, V1, 2), the control signal PTX_H1_V1_2 transitions tothe H level and, at the same time, the S-R latch circuit 1505 is set,and the control signal PTX_SRQ_H1_V1_2 transitions to the H level.

Subsequently, at time t30, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the H-levelcontrol signal PTX_DQ_H1_V1_2 in response to the H-level control signalPTX_SRQ_H1_V1_2. Thereby, the control signal PTX_H1_V1_2 that is theoutput signal of the OR gate for output 1507 transitions to the H level.Time t30 is the start timing of a reset period of the photoelectricconverters PD of the pixels P belonging to the second row.

Subsequently, at time t31, the control signal PTX_READ_V1_3 for thethird pixel row is controlled to the H level. Thereby, in the selectcircuit 1301(H1, V1, 3), the control signal PTX_H1_V1_3 transitions tothe H level and, at the same time, the S-R latch circuit 1505 is set,and the control signal PTX_SRQ_H1_V1_3 transitions to the H level.

Subsequently, at time t32, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the H-levelcontrol signal PTX_DQ_H1_V1_3 in response to the H-level control signalPTX_SRQ_H1_V1_3. Thereby, the control signal PTX_H1_V1_3 that is theoutput signal of the OR gate for output 1507 transitions to the H level.Time t32 is the start timing of a reset period of the photoelectricconverters PD of the pixels P belonging to the third row.

Next, at time t31, the control signal PTX_SH1_V1_1 for the first pixelrow is controlled to the H level. The control signal PTX_SH1_V1_1corresponds to the first shutter operation (SH1). At the timing when thecontrol signal PTX_SH1_V1_1 transitions to the H level, the controlsignal PTHR_SH1_H1 is already at the H level. This indicates that thecontrol signal PTX_SH1_V1_1 is enabled. Thereby, at time t31, thecontrol signals PTX_SH_H1_V1_1 transitions to the H level. In the selectcircuit 1301, the S-R latch circuit 1505 is reset, and the controlsignal PTX_SRQ_H1_V1_1 transitions to the L level.

Subsequently, at time t32, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the L-levelcontrol signal PTX_DQ_H1_V1_1 in response to the L-level control signalPTX_SRQ_H1_V1_1. Thereby, the control signal PTX_H1_V1_1 that is theoutput signal of the OR gate for output 1507 transitions to the L level.That is, time t32 is the end timing of the reset period and also thestart timing of an exposure period in the photoelectric converters PD ofthe pixels P belonging to the first row.

Subsequently, at time t33, the control signal PTX_SH1_V1_2 for thesecond pixel row is controlled to the H level. The control signalPTX_SH1_V1_2 corresponds to the first shutter operation (SH1). At thetiming when the control signal PTX_SH1_V1_2 transitions to the H level,the control signal PTHR_SH1_H1 is already at the H level. This indicatesthat the control signal PTX_SH1_V1_2 is enabled. Thereby, at time t33,the control signals PTX_SH_H1_V1_2 transitions to the H level. In theselect circuit 1301, the S-R latch circuit 1505 is reset, and thecontrol signal PTX_SRQ_H1_V1_2 transitions to the L level.

Subsequently, at time t34, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the L-levelcontrol signal PTX_DQ_H1_V1_2 in response to the L-level control signalPTX_SRQ_H1_V1_2. Thereby, the control signal PTX_H1_V1_2 that is theoutput signal of the OR gate for output 1507 transitions to the L level.That is, time t34 is the end timing of the reset period and also thestart timing of an exposure period in the photoelectric converters PD ofthe pixels P belonging to the second row.

Subsequently, at time t35, the control signal PTX_SH1_V1_3 for the thirdpixel row is controlled to the H level. The control signal PTX_SH1_V1_3corresponds to the first shutter operation (SH1). At the timing when thecontrol signal PTX_SH1_V1_3 transitions to the H level, the controlsignal PTHR_SH1_H1 is already at the H level. This indicates that thecontrol signal PTX_SH1_V1_3 is enabled. Thereby, at time t35, thecontrol signals PTX_SH_H1_V1_3 transitions to the H level. In the selectcircuit 1301, the S-R latch circuit 1505 is reset, and the controlsignal PTX_SRQ_H1_V1_3 transitions to the L level.

Subsequently, at time t36, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the L-levelcontrol signal PTX_DQ_H1_V1_3 in response to the L-level control signalPTX_SRQ_H1_V1_3. Thereby, the control signal PTX_H1_V1_3 that is theoutput signal of the OR gate for output 1507 transitions to the L level.That is, time t36 is the end timing of the reset period and also thestart timing of an exposure period in the photoelectric converters PD ofthe pixels P belonging to the third row.

Subsequently, at time t37, the control signals PTX_SH2_V1_1 for thefirst pixel row is controlled to the H level. At subsequent time t39,the control signals PTX_SH2_V1_2 for the second pixel row is controlledto the H level. At subsequent time t41, the control signals PTX_SH2_V1_3for the third pixel row is controlled to the H level. The controlsignals PTX_SH2_V1_1, PTX_SH2_V1_2, and PTX_SH2_V1_3 correspond to thesecond shutter operation (SH2).

At timings when the control signals PTX_SH2_V1_1, PTX_SH2_V1_2, andPTX_SH2_V1_3 transition to the H level, the control signals PTHR_SH2_H1is already at the L level. This indicates that the control signalsPTX_SH2_V1_1, PTX_SH2_V1_2, and PTX_SH2_V1_3 are disabled. Thereby, thecontrol signal PTX_SH_H1_V1_1 remains at the L level at time t37.Further, the control signal PTX_SH_H1_V1_2 remains at the L level attime t39. Further, the control signal PTX_SH_H1_V1_3 remains at the Llevel at time t41. Note that since the operation “SH1” is enabled andthe operation “SH2” is disabled, the exposure period is an exposureperiod of long-time exposure.

At subsequent time t49, t50, t51, t52, t53, and t54, the same operationsas those at time t27, t28, t29, t30, t31, and t32 are performed. Theseoperations cause the control signals PTX_READ_V1_1, PTX_READ_V1_2, andPTX_READ_V1_3 transition to the H level, the L level, and the H level inthis order, respectively. This operation is a read operation to read outcharge accumulated in the photoelectric converter PD. The exposureperiods on respective rows end upon the completion of this readoperation.

Further, the operations at time t53, t54, t55, t56, t57, t58, t59, andt60 are the same as the operations at time t31, t32, t33, t34, t35, t36,t37, and t38.

Next, the operation of the pixel block row V2 will be described by usingFIG. 22. First, at time t33, the control signal PTX_READ_V2_1 for thefirst pixel row is controlled to the H level. Thereby, in the selectcircuit 1301(H1, V2, 1), the control signal PTX_H1_V2_1 transitions tothe H level and, at the same time, the S-R latch circuit 1505 is set,and the control signal PTX_SRQ_H1_V2_1 transitions to the H level.

Subsequently, at time t34, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the H-levelcontrol signal PTX_DQ_H1_V2_1 in response to the H-level control signalPTX_SRQ_H1_V2_1. Thereby, the control signal PTX_H1_V2_1 that is theoutput signal of the OR gate for output 1507 transitions to the H level.Time t34 corresponds to the start timing of a reset period of thephotoelectric converters PD in the pixels P belonging to the first row.

Subsequently, at time t35, the control signal PTX_READ_V2_2 for thesecond pixel row is controlled to the H level. Thereby, in the selectcircuit 1301(H1, V2, 2), the control signal PTX_H1_V2_2 transitions tothe H level and, at the same time, the S-R latch circuit 1505 is set,and the control signal PTX_SRQ_H1_V2_2 transitions to the H level.

Subsequently, at time t36, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the H-levelcontrol signal PTX_DQ_H1_V2_2 in response to the H-level control signalPTX_SRQ_H1_V2_2. Thereby, the control signal PTX_H1_V2_2 that is theoutput signal of the OR gate for output 1507 transitions to the H level.Time t36 is the start timing of a reset period of the photoelectricconverters PD of the pixels P belonging to the second row.

Subsequently, at time t37, the control signal PTX_READ_V2_3 for thethird pixel row is controlled to the H level. Thereby, in the selectcircuit 1301(H1, V2, 3), the control signal PTX_H1_V2_3 transitions tothe H level and, at the same time, the S-R latch circuit 1505 is set,and the control signal PTX_SRQ_H1_V2_3 transitions to the H level.

Subsequently, at time t38, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the H-levelcontrol signal PTX_DQ_H1_V2_3 in response to the H-level control signalPTX_SRQ_H1_V2_3. Thereby, the control signal PTX_H1_V2_3 that is theoutput signal of the OR gate for output 1507 transitions to the H level.Time t38 is the start timing of a reset period of the photoelectricconverters PD of the pixels P belonging to the third row.

Next, at time t37, the control signal PTX_SH1_V2_1 for the first pixelrow is controlled to the H level. At subsequent time t39, the controlsignal PTX_SH1_V2_2 for the second pixel row is controlled to the Hlevel. At subsequent time t41, the control signal PTX_SH1_V2_3 for thethird pixel row is controlled to the H level. The control signalsPTX_SH1_V2_1, PTX_SH1_V2_2, and PTX_SH1_V2_3 correspond to the firstshutter operation (SH1).

At the timing when the control signals PTX_SH1_V2_1, PTX_SH1_V2_2, andPTX_SH1_V2_3 transition to the H level, the control signal PTHR_SH1_H1is already at the L level. This indicates that the control signalsPTX_SH1_V2_1, PTX_SH1_V2_2, and PTX_SH1_V2_3 are disabled. Thereby, attime t37, the control signal PTX_SH_H1_V2_1 remains at the L level.Further, at time t39, the control signal PTX_SH_H1_V2_2 remains at the Llevel. Further, at time t41, the control signal PTX_SH_H1_V2_3 remainsat the L level.

Subsequently, at time t43, the control signals PTX_SH2_V2_1 for thefirst pixel row is controlled to the H level. The control signalPTX_SH2_V2_1 corresponds to the second shutter operation (SH2). At thetiming when the control signal PTX_SH2_V2_1 transitions to the H level,the control signal PTHR_SH2_H1 is already at the H level. This indicatesthat the control signal PTX_SH2_V2_1 is enabled. Thereby, at time t43,the control signal PTX_SH_H1_V2_1 transitions to the H level. In theselect circuit 1301, the S-R latch circuit 1505 is reset, and thecontrol signal PTX_SRQ_H1_V2_1 transitions to the L level.

Subsequently, at time t44, the control signal PLAT__D transitions to theH level, and thereby the D latch circuit 1506 outputs the L-levelcontrol signal PTX_DQ_H1_V2_1 in response to the L-level control signalPTX_SRQ_H1_V2_1. Thereby, the control signal PTX_H1_V2_1 that is theoutput signal of the OR gate for output 1507 transitions to the L level.That is, time t44 is the end timing of the reset period and also thestart timing of an exposure period in the photoelectric converters PD ofthe pixels P belonging to the first row. Note that, since the operation“SH2” is enabled, this exposure period is an exposure period ofshort-time exposure.

Subsequently, at time t45, the control signals PTX_SH2_V2_2 for thesecond pixel row is controlled to the H level. The control signalPTX_SH2_V2_2 corresponds to the second shutter operation (SH2). At thetiming when the control signal PTX_SH2_V2_2 transitions to the H level,the control signal PTHR_SH2_H1 is already at the H level. This indicatesthat the control signal PTX_SH2_V2_2 is enabled. Thereby, at time t45,the control signal PTX_SH_H1_V2_2 transitions to the H level. In theselect circuit 1301, the S-R latch circuit 1505 is reset, and thecontrol signal PTX_SRQ_H1_V2_2 transitions to the L level.

Subsequently, at time t46, the control signal PLAT__D transitions to theH level, and thereby the D latch circuit 1506 outputs the L-levelcontrol signal PTX_DQ_H1_V2_2 in response to the L-level control signalPTX_SRQ_H1_V2_2. Thereby, the control signal PTX_H1_V2_2 that is theoutput signal of the OR gate for output 1507 transitions to the L level.That is, time t46 is the end timing of the reset period and also thestart timing of an exposure period in the photoelectric converters PD ofthe pixels P belonging to the second row. Note that, since the operation“SH2” is enabled, this exposure period is an exposure period ofshort-time exposure.

Subsequently, at time t47, the control signals PTX_SH2_V2_3 for thethird pixel row is controlled to the H level. The control signalPTX_SH2_V2_3 corresponds to the second shutter operation (SH2). At thetiming when the control signal PTX_SH2_V2_3 transitions to the H level,the control signal PTHR_SH2_H1 is already at the H level. This indicatesthat the control signal PTX_SH2_V2_3 is enabled. Thereby, at time t47,the control signal PTX_SH_H1_V2_3 transitions to the H level. In theselect circuit 1301, the S-R latch circuit 1505 is reset, and thecontrol signal PTX_SRQ_H1_V2_3 transitions to the L level.

Subsequently, at time t48, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the L-levelcontrol signal PTX_DQ_H1_V2_3 in response to the L-level control signalPTX_SRQ_H1_V2_3. Thereby, the control signal PTX_H1_V2_3 that is theoutput signal of the OR gate for output 1507 transitions to the L level.That is, time t48 is the end timing of the reset period and also thestart timing of an exposure period in the photoelectric converters PD ofthe pixels P belonging to the third row. Note that, since the operation“SH2” is enabled, this exposure period is an exposure period ofshort-time exposure.

At subsequent time t55, t56, t57, t58, t59, and t60, the same operationsas those at time t33, t34, t35, t36, t37, and t38 are performed. Thisoperation causes the control signals PTX_READ_V2_1, PTX_READ_V2_2, andPTX_READ_V2_3 transition to the H level, the L level, and the H level inthis order, respectively. This operation is a read operation to read outcharge accumulated in the photoelectric converter PD. The exposureperiods on respective rows end upon the completion of this readoperation.

FIG. 23 is a timing chart illustrating the operation of the selectcircuit block 302 H2. FIG. 23 illustrates only the operation of thepixel block row V 1. Note that the time axis is common to FIG. 21 toFIG. 23.

First, in the period from time t27 to time t27′, the control signalPTX_READ_V1_1 for the first pixel row is controlled to the H level.Thereby, in the select circuit 1301(H2, V1, 1), the control signalPTX_H2_V1_1 transitions to the H level and, at the same time, the S-Rlatch circuit 1505 is set, and the control signal PTX_SRQ_H2_V1_1transitions to the H level.

Subsequently, at time t28, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the H-levelcontrol signal PTX_DQ_H2_V1_1 in response to the H-level control signalPTX_SRQ_H2_V1_1. Thereby, the control signal PTX_H2_V1_1 that is theoutput signal of the OR gate for output 1507 transitions to the H level.Time t28 corresponds to the start timing of a reset period of thephotoelectric converters PD in the pixels P belonging to the first row.

Subsequently, at time t29, the control signal PTX_READ_V1_2 for thesecond pixel row is controlled to the H level. Thereby, in the selectcircuit 1301 (H2, V1, 2), the control signal PTX_H2_V1_2 transitions tothe H level and, at the same time, the S-R latch circuit 1505 is set andthe control signal PTX_SRQ_H2_V1_2 transitions to the H level.

Subsequently, at time t30, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the H-levelcontrol signal PTX_DQ_H2_V1_2 in response to the H-level control signalPTX_SRQ_H2_V1_2. Thereby, the control signal PTX_H2_V1_2 that is theoutput signal of the OR gate for output 1507 transitions to the H level.Time t30 is the start timing of a reset period of the photoelectricconverters PD of the pixels P belonging to the second row.

Subsequently, at time t31, the control signal PTX_READ_V1_3 for thethird pixel row is controlled to the H level. Thereby, in the selectcircuit 1301(H2, V1, 3), the control signal PTX_H2_V1_3 transitions tothe H level and, at the same time, the S-R latch circuit 1505 is set,and the control signal PTX_SRQ_H2_V1_3 transitions to the H level.

Subsequently, at time t32, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the H-levelcontrol signal PTX_DQ_H2_V1_3 in response to the H-level control signalPTX_SRQ_H2_V1_3. Thereby, the control signal PTX_H2_V1_3 that is theoutput signal of the OR gate for output 1507 transitions to the H level.Time t32 is the start timing of a reset period of the photoelectricconverters PD of the pixels P belonging to the third row.

Next, at time t31, the control signal PTX_SH1_V1_1 for the first pixelrow is controlled to the H level. At subsequent time t33, the controlsignal PTX_SH1_V1_2 for the second pixel row is controlled to the Hlevel. At subsequent time t35, the control signal PTX_SH1_V1_3 for thethird pixel row is controlled to the H level. The control signalsPTX_SH1_V1_1, PTX_SH1_V1_2, and PTX_SH1_V1_3 correspond to the firstshutter operation (SH1).

At timings when the control signals PTX_SH1_V1_1, PTX_SH1_V1_2, andPTX_SH1_V1_3 transition to the H level, the control signals PTHR_SH1_H2is already at the L level. This indicates that the control signalsPTX_SH1_V1_1, PTX_SH1_V1_2, and PTX_SH1_V1_3 are disabled. Thereby, attime t31, the control signal PTX_SH H2_V1_1 remains at the L level.Further, at time t33, the control signal PTX_SH H2_V1_2 remains at the Llevel. Further, at time t35, the control signal PTX_SH H2_V1_3 remainsat the L level.

Subsequently, at time t37, the control signals PTX_SH2_V1_1 for thefirst pixel row is controlled to the H level. The control signalPTX_SH2_V1_1 corresponds to the second shutter operation (SH2). At thetiming when the control signal PTX_SH2_V1_1 transitions to the H level,the control signal PTHR_SH2_H2 is already at the H level. This indicatesthat the control signal PTX_SH2_V1_1 is enabled. Thereby, at time t38,the control signal PTX_SH H2_V1_1 transitions to the H level. In theselect circuit 1301, the S-R latch circuit 1505 is reset, and thecontrol signal PTX_SRQ_H2_V1_1 transitions to the L level.

Subsequently, at time t38, the control signal PLAT__D transitions to theH level, and thereby the D latch circuit 1506 outputs the L-levelcontrol signal PTX_DQ_H2_V1_1 in response to the L-level control signalPTX_SRQ_H2_V1_1. Thereby, the control signal PTX_H2_V1_1 that is theoutput signal of the OR gate for output 1507 transitions to the L level.That is, time t38 is the end timing of the reset period and also thestart timing of an exposure period in the photoelectric converters PD ofthe pixels P belonging to the first row. Note that, since the operation“SH2” is enabled, this exposure period is an exposure period ofshort-time exposure.

Subsequently, at time t39, the control signals PTX_SH2_V1_2 for thesecond pixel row is controlled to the H level. The control signalPTX_SH2_V1_2 corresponds to the second shutter operation (SH2). At thetiming when the control signal PTX_SH2_V1_2 transitions to the H level,the control signal PTHR_SH2_H2 is already at the H level. This indicatesthat the control signal PTX_SH2_V1_2 is enabled. Thereby, at time t39,the control signal PTX_SH H2_V1_2 transitions to the H level. In theselect circuit 1301, the S-R latch circuit 1505 is reset, and thecontrol signal PTX_SRQ_H2_V1_2 transitions to the L level.

Subsequently, at time t40, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the L-levelcontrol signal PTX_DQ_H2_V1_2 in response to the L-level control signalPTX_SRQ_H2_V1_2. Thereby, the control signal PTX_H2_V1_2 that is theoutput signal of the OR gate for output 1507 transitions to the L level.That is, time t40 is the end timing of the reset period and also thestart timing of an exposure period in the photoelectric converters PD ofthe pixels P belonging to the second row. Note that, since the operation“SH2” is enabled, this exposure period is an exposure period ofshort-time exposure.

Subsequently, at time t41, the control signals PTX_SH2_V1_3 for thethird pixel row is controlled to the H level. The control signalPTX_SH2_V1_3 corresponds to the third shutter operation (SH2). At thetiming when the control signal PTX_SH2_V1_3 transitions to the H level,the control signal PTHR_SH2_H2 is already at the H level. This indicatesthat the control signal PTX_SH2_V1_3 is enabled. Thereby, at time t41,the control signal PTX_SH H2_V1_3 transitions to the H level. In theselect circuit 1301, the S-R latch circuit 1505 is reset, and thecontrol signal PTX_SRQ_H2_V1_3 transitions to the L level.

Subsequently, at time t42, the control signal PLAT_D transitions to theH level, and thereby the D latch circuit 1506 outputs the L-levelcontrol signal PTX_DQ_H2_V1_3 in response to the L-level control signalPTX_SRQ_H2_V1_3. Thereby, the control signal PTX_H2_V1_3 that is theoutput signal of the OR gate for output 1507 transitions to the L level.That is, time t42 is the end timing of the reset period and also thestart timing of an exposure period in the photoelectric converters PD ofthe pixels P belonging to the third row. Note that, since the operation“SH2” is enabled, this exposure period is an exposure period ofshort-time exposure.

At subsequent time t49, t50, t51, t52, t53, and t54, the same operationsas those at time t27, t28, t29, t30, t31, and t32 are performed. Theseoperations cause the control signals PTX_READ_V1_1, PTX_READ_V1_2, andPTX_READ_V1_3 to transition to the H level, the L level, and the H levelin this order, respectively. This operation is a read operation to readout charge accumulated in the photoelectric converter PD. The exposureperiods on respective rows end upon the completion of this readoperation.

In the present embodiment, in a read operation, the operation to controlthe control signal PTX to the H level, the L level, and the H level inthis order is performed. That is, in the first H level period, chargeaccumulated in the photoelectric converter PD is transferred to thefloating diffusion FD during an exposure period. In the next L levelperiod, readout of a signal based on the potential of the floatingdiffusion FD is then performed. Then, the control signal PTX iscontrolled back to the H level to start reset of the photoelectricconverter PD. In terms of holding the photoelectric converter PD in areset state during a period other than an exposure period, while it maybe possible to hold the control signal PTX to the H level at the time ofreadout of accumulated charge, the present embodiment causes the controlsignal to once transition to the L level at the time of readout ofaccumulated charge.

The advantage obtained by such driving is obtained when readout of asignal based on reset noise is performed. Here, reset noise means anoise component that is undesirably added when charge accumulated in thephotoelectric converter PD are read out to the floating diffusion FD.Thus, in most imaging devices, a signal based on reset noise is acquiredin advance, and a signal based on the actual amount of chargeaccumulated in the photoelectric converter PD is acquired by subtractingthe signal based on reset noise from a signal based on chargetransferred to the floating diffusion FD in the post-stage circuit. Itis therefore desirable that the state of the floating diffusion FD bethe same between the time of readout of the signal based on chargetransferred to the floating diffusion FD and the time of readout of thesignal based on reset noise. Since the control signal PTX is controlledto the L level at the time of readout of the signal based on resetnoise, it is desirable to control the control signal PTX to the L levelalso at the time of readout of the signal based on charge transferred tothe floating diffusion FD.

As described above, according to the present embodiment, it is possibleto control the control signal PTX to the L level at the time of readoutof the actual charge. Therefore, when driving to read out reset noise ofthe floating diffusion FD as described above is performed, it ispossible to read out only the amount of the actual charge accumulated inthe photoelectric converter PD after calculating a difference betweenrespective signals by the post-stage circuit.

Sixth Embodiment

An imaging system according to a sixth embodiment of the presentinvention will be described with reference to FIG. 24. FIG. 24 is ablock diagram illustrating a general configuration of the imaging systemaccording to the present embodiment.

The photoelectric conversion device 100 described in the first to fifthembodiments described above can be applied to various imaging systems.Examples of applicable imaging systems may include a digital stillcamera, a digital camcorder, a surveillance camera, a copying machine, afax machine, a mobile phone, an on-vehicle camera, an observationsatellite, and the like. In addition, a camera module including anoptical system such as a lens and an imaging device is also included inthe imaging system. FIG. 24 illustrates a block diagram of a digitalstill camera as an example out of these examples.

An imaging system 400 illustrated as an example in FIG. 24 includes animaging device 401, a lens 402 that captures an optical image of anobject onto the imaging device 401, an aperture 404 for changing a lightamount passing through the lens 402, and a barrier 406 for protectingthe lens 402. The lens 402 and the aperture 404 form an optical systemthat converges a light onto the imaging device 401. The imaging device401 is the photoelectric conversion device 100 described in any of thefirst to fifth embodiments and converts an optical image captured by thelens 402 into image data.

Further, the imaging system 400 includes a signal processing unit 408that processes an output signal output from the imaging device 401. Thesignal processing unit 408 preforms analog-to-digital (AD) conversionthat converts an analog signal output from the imaging device 401 into adigital signal. Further, the signal processing unit 408 performs anoperation to perform various correction or compression and output imagedata, if necessary. The AD conversion unit that is a part of the signalprocessing unit 408 may be formed on a semiconductor substrate on whichthe imaging device 401 is provided or formed on a semiconductorsubstrate separately from the imaging device 401. Further, the imagingdevice 401 and the signal processing unit 408 may be formed on the samesemiconductor substrate.

Furthermore, the imaging system 400 includes a memory unit 410 fortemporarily storing image data therein and an external interface unit(external I/F unit) 412 for communicating with an external computer orthe like. The imaging system 400 further includes a storage medium 414such as a semiconductor memory for performing storage or readout ofimaging data and a storage medium control interface unit (storage mediumcontrol I/F unit) 416 for performing storage or readout on the storagemedium 414. Note that the storage medium 414 may be embedded in theimaging system 400 or may be removable.

Furthermore, the imaging system 400 includes a general control/operationunit 418 that performs various calculation and controls the entiredigital still camera and a timing generation unit 420 that outputsvarious timing signals to the imaging device 401 and the signalprocessing unit 408. Here, the timing signal or the like may be inputfrom the outside, and the imaging system 400 may include at least theimaging device 401 and the signal processing unit 408 that processes anoutput signal output from the imaging device 401.

The imaging device 401 outputs an imaging signal to the signalprocessing unit 408. The signal processing unit 408 performspredetermined signal processing on an imaging signal output from theimaging device 401 and outputs image data. The signal processing unit408 uses an imaging signal to generate an image. Further, in the signalprocessing unit 408, a high dynamic range image may be composed based onsignals acquired from the pixels P of the pixel blocks 201 havingdifferent lengths of exposure periods.

As described above, according to the present embodiment, the imagingsystem to which the photoelectric conversion device 100 according to thefirst to fifth embodiment is applied can be realized.

Seventh Embodiment

An imaging system and a movable object according to a seventh embodimentof the present invention will be described by using FIG. 25A and FIG.25B. FIG. 25A is a diagram illustrating a configuration of the imagingsystem according to the present embodiment. FIG. 25B is a diagramillustrating a configuration of the movable object according to thepresent embodiment.

FIG. 25A illustrates an example of an imaging system related to anon-vehicle camera. An imaging system 500 includes an imaging device 510.The imaging device 510 is the photoelectric conversion device 100described in any of the above first to fifth embodiments. The imagingsystem 500 includes an image processing unit 512 that performs imageprocessing on a plurality of image data acquired by the imaging device510 and a parallax acquisition unit 514 that calculates a parallax (aphase difference of parallax images) from the plurality of image dataacquired by the imaging system 500. Further, the imaging system 500includes a distance acquisition unit 516 that calculates a distance tothe object based on the calculated parallax and a collisiondetermination unit 518 that determines whether or not there is acollision possibility based on the calculated distance. Here, theparallax acquisition unit 514 and the distance acquisition unit 516 arean example of a distance information acquisition unit that acquiresdistance information on the distance to the object. That is, thedistance information is information on a parallax, a defocus amount, adistance to an object, or the like. The collision determination unit 518may use any of the distance information to determine the collisionpossibility. The distance information acquisition unit may beimplemented by dedicatedly designed hardware or may be implemented by asoftware module. Further, the distance information acquisition unit maybe implemented by a Field Programmable Gate Array (FPGA), an ApplicationSpecific Integrated Circuit (ASIC), or the like or may be implemented bya combination thereof

The imaging system 500 is connected to the vehicle informationacquisition device 520 and can acquire vehicle information such as avehicle speed, a yaw rate, a steering angle, or the like. Further, theimaging system 500 is connected to a control ECU 530, which is a controldevice that outputs a control signal for causing a vehicle to generatebraking force based on a determination result by the collisiondetermination unit 518. Further, the imaging system 500 is alsoconnected to an alert device 540 that issues an alert to the driverbased on a determination result by the collision determination unit 518.For example, when the collision probability is high as the determinationresult of the collision determination unit 518, the control ECU 530performs vehicle control to avoid a collision or reduce damage byapplying a brake, pushing back an accelerator, suppressing engine power,or the like. The alert device 540 alerts a user by sounding an alertsuch as a sound, displaying alert information on a display of a carnavigation system or the like, providing vibration to a seat belt or asteering wheel, or the like.

In the present embodiment, an area around a vehicle, for example, afront area or a rear area is captured by using the imaging system 500.FIG. 25B illustrates the imaging system when a front area of a vehicle(a capturing area 550) is captured. The vehicle information acquisitiondevice 520 transmits an instruction to the imaging system 500 or theimaging device 510. Such a configuration can further improve the rangingaccuracy.

Although the example of control for avoiding a collision to anothervehicle has been described above, the embodiment is applicable toautomatic driving control for following another vehicle, automaticdriving control for not going out of a traffic lane, or the like.Furthermore, the imaging system is not limited to a vehicle such as thesubject vehicle and can be applied to a movable object (movingapparatus) such as a ship, an airplane, or an industrial robot, forexample. In addition, the imaging system can be widely applied to adevice which utilizes object recognition, such as an intelligenttransportation system (ITS), without being limited to movable objects.

Modified Embodiments

The present invention is not limited to the embodiments described above,and various modifications are possible.

For example, an example in which a part of the configuration of any ofthe embodiments is added to another embodiment or an example in which apart of the configuration of any of the embodiments is replaced with apart of the configuration of another embodiment is also one of theembodiments of the present invention.

Further, the select circuit 1301 and the control signal thereof are notlimited to the configuration example illustrated in FIG. 15 or FIG. 20and may be modified appropriately as far as the same advantage as theadvantage described in each embodiment may be realized.

Further, the imaging systems illustrated in the above sixth and seventhembodiments are examples of an imaging system to which the photoelectricconversion device of the present invention may be applied, and animaging system to which the photoelectric conversion device of thepresent invention can be applied is not limited to the configurationillustrated in FIG. 24 and FIG. 25A.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2018-213989, filed Nov. 14, 2018, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A photoelectric conversion device comprising: apixel unit in which a plurality of pixels are arranged to form aplurality of rows and a plurality of columns and each of the pluralityof pixels includes a photoelectric converter that generates charge byphotoelectric conversion, an output unit that outputs a signal inaccordance with an amount of charge, and a transfer transistor thattransfers charge in the photoelectric converter to the output unit; anda pixel control unit that controls operations of the plurality ofpixels, wherein the pixel unit includes a plurality of pixel blocks eachincluding one or more of the pixels, wherein the pixel control unitincludes select circuits respectively associated to the plurality ofpixel blocks, each of the select circuits being configured to select acontrol signal to be supplied to the pixels of a corresponding pixelblock, wherein the pixel control unit is configured to supply, to thepixels of each of the plurality of pixel blocks, a control signal inaccordance with an exposure period individually defined for theplurality of pixel blocks, wherein the pixel control unit is configuredto read out, from each of the plurality of pixels, a first signalobtained when the photoelectric converter is in a reset state and asecond signal based on charge accumulated in the photoelectric converterduring the exposure period, wherein a period excluding both the exposureperiod and a period in which the second signal is being read outcorresponds to a reset period of the photoelectric converter in whichthe photoelectric converter is being in the reset state, and wherein thetransfer transistor is in an off-state in a period in which the firstsignal is read out and a period in which the second signal is read out.2. The photoelectric conversion device according to claim 1, whereineach of the select circuits includes at least two signal level holdingunits each configured to generate a control signal supplied to thetransfer transistor of the pixels belonging to the corresponding pixelblock.
 3. A photoelectric conversion device comprising: a pixel unit inwhich a plurality of pixels are arranged to form a plurality of rows anda plurality of columns and each of the plurality of pixels includes aphotoelectric converter that generates charge by photoelectricconversion, an output unit that outputs a signal in accordance with anamount of charge, and a transfer transistor that transfers charge in thephotoelectric converter to the output unit; and a pixel control unitthat controls operations of the plurality of pixels, wherein the pixelunit includes a plurality of pixel blocks each including one or more ofthe pixels, wherein the pixel control unit includes select circuitsrespectively associated to the plurality of pixel blocks, each of theselect circuits being configured to select a control signal to besupplied to the pixels of a corresponding pixel block, wherein the pixelcontrol unit is configured to supply, to the pixels of each of theplurality of pixel blocks, a control signal in accordance with anexposure period individually defined for the plurality of pixel blocks,wherein a period excluding both the exposure period and a period inwhich a signal based on charge accumulated in the photoelectricconverter during the exposure period is being read out corresponds to areset period of the photoelectric converter in which the photoelectricconverter is being in the reset state, and wherein each of the selectcircuits includes at least two signal level holding units eachconfigured to generate a control signal supplied to the transfertransistor of the pixels belonging to the corresponding pixel block. 4.The photoelectric conversion device according to claim 2, wherein afirst signal level holding unit arranged on a pre-stage out of the twosignal level holding units included in the select circuits holds a levelof an output signal at a High level during a period from a rising edgeof a control signal indicating a read timing to a rising edge of acontrol signal indicating an effective reset timing.
 5. Thephotoelectric conversion device according to claim 3, wherein a firstsignal level holding unit arranged on a pre-stage out of the two signallevel holding units included in the select circuits holds a level of anoutput signal at a High level during a period from a rising edge of acontrol signal indicating a read timing to a rising edge of a controlsignal indicating an effective reset timing.
 6. The photoelectricconversion device according to claim 4, wherein a second signal levelholding unit arranged on a post-stage out of the two signal levelholding units included in the select circuits holds a level of an outputsignal at a High level in accordance with an output signal of the firstsignal level holding unit and a timing control signal indicating a starttiming of the reset period of the photoelectric converter.
 7. Thephotoelectric conversion device according to claim 5, wherein a secondsignal level holding unit arranged on a post-stage out of the two signallevel holding units included in the select circuits holds a level of anoutput signal at a High level in accordance with an output signal of thefirst signal level holding unit and a timing control signal indicating astart timing of the reset period of the photoelectric converter.
 8. Thephotoelectric conversion device according to claim 6, wherein the timingcontrol signal is input commonly to all the select circuits.
 9. Thephotoelectric conversion device according to claim 7, wherein the timingcontrol signal is input commonly to all the select circuits.
 10. Thephotoelectric conversion device according to claim 1 further comprising:a first substrate on which at least the pixel unit is provided; and asecond substrate on which at least the select circuits are provided,wherein the first substrate and the second substrate are stacked on eachother.
 11. The photoelectric conversion device according to claim 9,wherein each of a plurality of pixel control lines connecting the pixelcontrol unit and the pixel unit to each other is connected via oneconnection node at a boundary between the first substrate and the secondsubstrate and connected to a common signal line connecting the pluralityof pixels arranged on the same row of the same pixel block on the firstsubstrate.
 12. The photoelectric conversion device according to claim 1,wherein a region in which the pixel unit is provided and a region inwhich the select circuits are provided do not overlap each other in aplan view.
 13. The photoelectric conversion device according to claim 1,wherein all of lengths of signal lines that supply control signals fromthe pixel control unit to transfer transistors of the pixels are thesame.
 14. The photoelectric conversion device according to claim 1,wherein the plurality of pixel blocks are arranged in the pixel unit soas to form a plurality of rows and a plurality of columns.
 15. Animaging system comprising: the photoelectric conversion device accordingto claim 1; and a signal processing unit that processes signals outputfrom the pixels of the photoelectric conversion device.
 16. The imagingsystem according to claim 12, wherein the signal processing unitcomposes a high dynamic range image based on signals acquired from thepixel blocks having different lengths of the exposure period.
 17. Amovable object comprising: the photoelectric conversion device accordingto claim 1; a distance information acquisition unit that acquiresdistance information on a distance to an object, from a parallax imagebased on signals from the photoelectric conversion device; and a controlunit that controls the movable object based on the distance information.18. An imaging system comprising: the photoelectric conversion deviceaccording to claim 3; and a signal processing unit that processessignals output from the pixels of the photoelectric conversion device.19. The imaging system according to claim 18, wherein the signalprocessing unit composes a high dynamic range image based on signalsacquired from the pixel blocks having different lengths of the exposureperiod.
 20. A movable object comprising: the photoelectric conversiondevice according to claim 3; a distance information acquisition unitthat acquires distance information on a distance to an object, from aparallax image based on signals from the photoelectric conversiondevice; and a control unit that controls the movable object based on thedistance information.